From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Confirming the successful results of an experimental dynamo test for a Bentley vehicle.
| Identifier | ExFiles\Box 168a\3\ img159 | |
| Date | 27th February 1935 | |
| To Hs{Lord Ernest Hives - Chair}/Wst. from E.{Mr Elliott - Chief Engineer} WST 6099 E.5/HP.27.2.35. c. Sg{Arthur F. Sidgreaves - MD}, Wop, Hs{Lord Ernest Hives - Chair} By, By/RD re Dynamos. This is to confirm that I have seen in the Lab. this morning the experimental 5" dynamo with 3.1 diameter armature and 12 conductors per slot running at 5625 r.p.m. with commendable absence of sparking compared with the standard machine running at 4500 r.p.m., the output of the former being hotted up to 20 amperes with still satisfactory results in respect to commutation. This experiment demonstrates two things:- (1) that the improved Bentley dynamo with 3.1 diameter armature and 16 conductors per slot and more rigid field also equipped with the chamfered poles is likely to give satisfactory high speed commutation, as well as the earlier cutting-in desired. This machine should be pushed forward as rapidly as possible as it is our complete answer on standard production to the present situation where we want earlier cutting-in without sacrifice of top speed performance, with the dynamo geared 1 to 1. (2) This also tells us that we can push ahead with the scheme for increasing the dynamo ratio from 1 to 1 1/4 without fear of bad commutation at high speeds. This scheme is envisaged for future Bentleys and has always been coupled with a smaller and lighter dynamo. We shall now want to know if the specification of the smaller and lighter dynamo running at the higher speed will give us the same cutting-in and performance as the improved machine mentioned in (1). ? (1 1/2? Driven at 1 1/2 = 11 m.p.h.) E.{Mr Elliott - Chief Engineer} | ||